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Cited by 156Muscle metabolism and nutritionSports Performance and TrainingExercise and Physiological Responses

THE EFFECTS OF PROTEIN AND AMINO ACID SUPPLEMENTATION ON PERFORMANCE AND TRAINING ADAPTATIONS DURING TEN WEEKS OF RESISTANCE TRAINING

KERKSICK, CHAD M., RASMUSSEN, CHRISTOPHER J., LANCASTER, STACY L., MAGU, BHARAT, SMITH, PENNEY, MELTON, CHARLES, GREENWOOD, MICHAEL, ALMADA, ANTHONY L. +2 more·2006·Journal of Strength and Conditioning Research
DOI 10.1519/00124278-200608000-00028
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Abstract

The purpose of this study was to examine the effects of whey protein supplementation on body composition, muscular strength, muscular endurance, and anaerobic capacity during 10 weeks of resistance training. Thirty-six resistance-trained males (31.0 +/- 8.0 years, 179.1 +/- 8.0 cm, 84.0 +/- 12.9 kg, 17.8 +/- 6.6%) followed a 4 days-per-week split body part resistance training program for 10 weeks. Three groups of supplements were randomly assigned, prior to the beginning of the exercise program, in a double-blind manner to all subjects: 48 g per day (g.d(-1)) carbohydrate placebo (P), 40 g.d(-1) of whey protein + 8 g.d(-1) of casein (WC), or 40 g.d(-1) of whey protein + 3 g.d(-1) branched-chain amino acids + 5 g.d(-1) L-glutamine (WBG). At 0, 5, and 10 weeks, subjects were tested for fasting blood samples, body mass, body composition using dual-energy x-ray absorptiometry (DEXA), 1 repetition maximum (1RM) bench and leg press, 80% 1RM maximal repetitions to fatigue for bench press and leg press, and 30-second Wingate anaerobic capacity tests. No changes (p > 0.05) were noted in all groups for energy intake, training volume, blood parameters, and anaerobic capacity. WC experienced the greatest increases in DEXA lean mass (P = 0.0 +/- 0.9; WC = 1.9 +/- 0.6; WBG = -0.1 +/- 0.3 kg, p < 0.05) and DEXA fat-free mass (P = 0.1 +/- 1.0; WC = 1.8 +/- 0.6; WBG = -0.1 +/- 0.2 kg, p < 0.05). Significant increases in 1RM bench press and leg press were observed in all groups after 10 weeks. In this study, the combination of whey and casein protein promoted the greatest increases in fat-free mass after 10 weeks of heavy resistance training. Athletes, coaches, and nutritionists can use these findings to increase fat-free mass and to improve body composition during resistance training.

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  • Multiple studies have reported that different forms of protein significantly increase fat-free mass while resistance training.

    “multiple studies have reported on the ability of different forms of protein to significantly increase fat-free mass while resistance training [70, 227–232].”

    From ISSN exercise &amp; sports nutrition review update: research &amp; recommendations (2018) · cites this paper as [232]

  • Many studies have agreed that post workout supplementation is vital to recovery and training adaptations.

    “In the last few years many studies have agreed that post workout supplementation is vital to recovery and training adaptations [133, 230, 232, 607, 608].”

    From ISSN exercise &amp; sports nutrition review update: research &amp; recommendations (2018) · cites this paper as [232]

  • The effects of supplemental protein consumption on maximal strength enhancement are varied, with a majority of investigations reporting no benefit and a few reporting improvements in maximal strength.

    “the effects of supplemental protein consumption has on maximal strength enhancement are varied, with a majority of the investigations reporting no benefit [15–25] and a few reporting improvements in maximal strength [26–29].”

    From International Society of Sports Nutrition Position Stand: protein and exercise (2017) · cites this paper as [22]

  • Many published investigations report that protein supplementation results in significant improvements in lean body weight/cross-sectional areas compared to placebo treatments.

    “many published investigations report that protein supplementation results in significant improvements in lean body weight/cross-sectional areas as compared to placebo treatments [15, 17, 21–23, 26, 27, 33, 37].”

    From International Society of Sports Nutrition Position Stand: protein and exercise (2017) · cites this paper as [22]

  • In a 10-week resistance training study, a combination of whey (40 g) and casein (8 g) yielded the greatest increase in fat-free mass (determined by DEXA) when compared to both a combination of 40 g of whey, 5 g of glutamine, and 3 g of BCAAs and a placebo consisting of 48 g of a maltodextrin carbohydrate.

    “For example, a 10-week resistance training study by Kerksick and colleagues [22] demonstrated that a combination of whey (40 g) and casein (8 g) yielded the greatest increase in fat-free mass (determined by DEXA) when compared to both a combination of 40 g of whey, 5 g of glutamine, and 3 g of BCAAs and a placebo consisting of 48 g of a maltodextrin carbohydrate.”

    From International Society of Sports Nutrition Position Stand: protein and exercise (2017) · cites this paper as [22]

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Authors
KERKSICK, C. M., RASMUSSEN, C. J., LANCASTER, S. L., MAGU, B., SMITH, P., MELTON, C., GREENWOOD, M., ALMADA, A. L., EARNEST, C. P., & KREIDER, R. B.
Affiliations
  • Baylor University (US)
  • Neuropsychopharmacologie (FR)
  • Cooper Institute (US)
ORCID
Venue
Journal of Strength and Conditioning Research
Publisher
Ovid Technologies (Wolters Kluwer Health)
Published
2006-08
Volume
20
Issue
3
Pages
643-653
ISSN
1064-8011 (ISSN-L)
DOI
10.1519/00124278-200608000-00028
OpenAlex
W2034215255
Cited by
156
References
8
Citations by year
2026: 2 · 2024: 6 · 2023: 5 · 2022: 7 · 2021: 3 · 2020: 10 · 2019: 10 · 2018: 8 · 2017: 10 · 2016: 5 · 2015: 12 · 2014: 15 · 2013: 12 · 2012: 10
FWCI
3.73
Type
journal article
Language
en
Open access
closed
Locations
  • The Journal of Strength and Conditioning Research (publishedVersion)
  • PubMed (publishedVersion)
Funders
Baylor University
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
  • Health Sciences › Medicine › Rehabilitation › Exercise and Physiological Responses
Keywords
whey protein supplementation, casein, branched-chain amino acids, glutamine, resistance training, body composition, fat-free mass, muscle strength, muscular endurance, anaerobic capacity, training effects, resistance-trained men, energy intake, training volume, blood parameters, lean body mass, Wingate test, bench press, leg press, one-repetition maximum
MeSH terms
Whey Proteins, Adaptation, Physiological, Adult, Amino Acids, Branched-Chain, Double-Blind Method, Glutamine, Humans, Male, Milk Proteins, Physical Education and Training, Uric Acid, Absorptiometry, Photon, Body Mass Index, Dietary Supplements, Muscle Strength

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